Most arguments for it are also "I would like it therefore it should happen."
I agree, neither of those arguments are useful. I feel like people here are the worst ambassors for their causes.
That being said, some people have pointed out mechanical and game design arguments against unlimited, non-optional world PvP:
Ganking, griefing, player number dependence and general disinterest in PvP content in the community (Regular battlegrounds are mostly empty in this game except at peak hours.)
There also seems to be an aversion to PvP in general.
I can only say its a polemic issue. Seems like vocal players here, either love PvP to death or absolutely hate it.
Which incidentally makes it a good trolling topic.